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Study of constituents of an alloy

Chemistry project undertaken by

SaHhil Sharma

XII-D

Delhi Public School, Dwarka


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Table of Contents

Cover Page ....................................................................................................................................... 1

Certificate......................................................................................................................................... 3

Acknowledgement........................................................................................................................ 4

Aim......................................................................................................................................................5

Introduction.................................................................................................................................... 6

Theoretical Background............................................................................................................. 7

Materials Required....................................................................................................................... 8Experiments and Observations............................................................................................... 9

Result/Conclusion..................................................................................................................... 11

References/Bibliography ....................................................................................................... 12


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Certificate

This is to certify that Sahil Sharma , student of Class XII-D, DelhiPublic School, Dwarka has completed the project titled Study of constituents

of an alloyduring the academic year 2011-2012 towards partial fulfillment of

credit for the Chemistry practical evaluation of AISSCE 2012, and submitted

satisfactory report, as compiled in the following pages, under my supervision.

Mrs Ila SharmaDept of Chemistry

DPS Dwarka


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Acknowledgement

I, Sahil Sharma ofclass XII -D express sincere gratitude to my school

authorities for allowing me to undertake the project titled Study of

constituents of an alloy. I naturally could not have done justice to my delicate

assignment, had I not been privileged to get the animate guidance from Mrs.

Ila Sharma, my chemistry teacher, and Mr. Rajesh, chemistry lab assistant.


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Aim

To study the consituents of an alloy ( Office All Pins ) utilizing the

principles of qualitative inorganic analysis.


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Introduction

An alloy is a homogeneous mixture of two or more metals or a metal and

non-metal. They are generally harder than their components with reduced

malleability and ductility. Alloys are prepared to enhance certain

characteristics of the constituent metals, as per requirement.

In this project, we shall qualitatively analyse the chemical composition of

Office All pins.


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Theoretical Background

An alloy is a mixture or metallic solid solution composed of two or moreelements. Complete solid solution alloys give single solid phase

microstructure, while partial solutions give two or more phases that may or

may not be homogeneous in distribution, depending on thermal (heat

treatment) history. Alloys usually have different properties from those of the

component elements.

Alloying a metal is done by combining it with one or more other metals or

non-metals that often enhance its properties. For example, steel is stronger

than iron, its primary element. The physical properties, such as density,reactivity, Young's modulus, and electrical and thermal conductivity, of an

alloy may not differ greatly from those of its elements, but engineering

properties such as tensile strength and shear strength may be substantially

different from those of the constituent materials. This is sometimes a result of

the sizes of the atoms in the alloy, because larger atoms exert a compressive

force on neighboring atoms, and smaller atoms exert a tensile force on their

neighbors, helping the alloy resist deformation. Sometimes alloys may exhibit

marked differences in behavior even when small amounts of one element

occur. Some alloys are made by melting and mixing two or more metals.Bronze, an alloy of copper and tin, was the first alloy discovered, during the

prehistoric period now known as the bronze age; it was harder than pure

copper and originally used to make tools and weapons. In later times bronze

has been used for ornaments,bells, statues, and bearings.

Curved pins have been used for over four thousand years. Originally, they

were fashioned out of iron and bone by the Sumerians and were used to holdclothes together. Later, these pins were also used to hold pages together bythreading the needle through their top corner. Many late pins were made ofbrass, a hard metal.


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Materials Required

Alloy pins to be studied Concentrated HNO3 For Group reagents:

Dilute HCl H2S solution Solid NH4Cl NH4OH (NH4)2CO3

K4Fe[(CN)6] Dilute NaOH Beakers Test tubes Other Chemicals


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Experiments and Observations

Though the composition of the coin is learnt to be Iron and Zinc, it was

analysed for presence of various metals.

S.No. Experiment Observations Comments

1 Dissolved a coin in

15 mL of

concentrated HNO3.

Vigorous reaction

takes place. Brown

fumes (NO2) are

evolved. Beaker getsheated up.

Light green coloured

clear solution is

finally obtained.

This is the sulution of

metal ions on which

further tests are

performed. Added waterto make the 50 mL of the

solution.

2 Took 5mL of

solution in a test

tube and added

dilute HCl.

No observed change Pb2+ is absent

3 Added

sulphuretted H2S to

the above solution

No observed changeis absentCu

4 Reddish- brown

precipitate

To 5mL original

solution solid

NH4Cl and excess of

NH4OH was added

Blood red colourlation Fe3+

2+

Fe3+

may be present

5 Took 5mL ofsolution in a test

tube and addedKSCN

is observed.

confirmed.

Fe3+

+ KSCN3 K+

3

+Fe(SCN)3


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6 To above solution

H2S was added

White precipitate

observed

May be due to formation

ofZnS

7 Dissolved the white

ppt in dilute HCl

and boiled offH2S

Whie precipitate

dissolves

ZnS(s) (white ppt) + 2HCl (aq.)

ZnCl2 (aq.) + 2H+(aq)+ S2-

(aq)

8 Added NaOH to

above solution

White precipitate

appears again

Zn2+confirmed.

ZnCl2 (aq) + 2NaOH(aq)

Zn(OH)2 (s) (white ppt) +

2NaCl(aq)

9 Added to original

solution (NH4)2CO3

in presence ofNH4Cl and NH4OH

No observable

change

Ca2+, Sr2+, Ba2+ are absent


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Result/Conclusion

The analysis of alloy pin confirms its composition to beIron and Zinc.


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References

Goyal Brothers Laboratory Manual in Chemistry.

Vogels Qualitative Inorganic Analysis

The Internet

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